Salinity ??

[sefrayser]

I have mixing my water to 1.025 and doing 5 gallon WC. I measured my salinity and its 1.023. I do not think my ATO is putting that much water to make it fluctuate that much. Is there anything that could eat the salt? I know I could put SW in my ATO but is that what I should do? I mixed up 2 gallons and I want to do a WC but if I mix it at say 1.027 will that be ok. I have a 34G tank so even a 2 gallon change wouldnt raise it that much. That may also be the reason why my MG is low and I cannot get it about 1260. I need a little advice.

[HighlandReefer]

Using salt mix as your top-off is a safe way to slowly raise your tank salinity. You can use this calculator as well:

http://www.hamzasreef.com/Contents/Calculators/SaltwaterTopOff.php

If you are skimming wet, this can reduce your salinity,especially if your skimmer goes crazy on you.

What are you using to measure your salinity with?

[bertoni]

All the skimmate removed needs to be replaced with saltwater, or the SG will rise over time.

[HighlandReefer]

"or the SG will rise over time."

You mean lower over time? :)

[bertoni]

Yes. Sigh! :)

[sefrayser]

I am using a ATI Refractor. Its calibrated correctly. I am not getting that much skimmate. I would estimate 5 oz a day. I do at least 9 gallons of water changes a week.

[HighlandReefer]

You loose salinity by organisms using alk, calcium and mag & other minor nutrients. If you maintain the parameters with supplementation & do proper water changes with matched salinity, then you will not see a decrease in salinity to much extent. Salt creep can account for some. Skimmers removing tank water will remove salinity. If you have an overflow mechanism for your tank, perhaps accidentally water can be dumped from the system.

[bertoni]

I'll guess there's about 20g in the tank. To drop the SG from 1.025 to 1.023 is an 8% drop. So you'd need to lose about 1.5 of saltwater and replace it with RO/DI to see that amount of drop. Of course, there's some inaccuracy in the refractometer. I'm not sure what's happening, but that's a lot of salt. Maybe we need some time frames to understand what's occurring.

[sefrayser]

I used the calculator and now I am a little confused. I put that I have 30 gallons of water and my salinity is 1.023 and I want 1.025, it said my ato water needs to be 1.014. Now if I do it by PPT( which I assume is the other reading on my ATC Refractometer. I put in 30 as my start and 35 for my target....it says it needs to be 37.5 which is 1.028.....what do I use?

[bertoni]

What calculator is this? Your water is a lot higher than 33 ppt, more like 34.

[HighlandReefer]

I used the calculator and now I am a little confused. I put that I have 30 gallons of water and my salinity is 1.023 and I want 1.025, it said my ato water needs to be 1.014. Now if I do it by PPT( which I assume is the other reading on my ATC Refractometer. I put in 30 as my start and 35 for my target....it says it needs to be 37.5 which is 1.028.....what do I use?

Water volume = tank actual water volume (system volume minus rock...etc)

Current Salinity - select the (sg) option and enter 1.023

Target salinity = select the sg option and enter 1.025

Water in your top off = the volume size of the top off container. If you want to do it over a larger period of time than you need to change it over two top-off container size and enter that amount. This is safer.

Top off salinity - pick the sg option again and this will tell you the sg (specific gravity you need in the top off container (option is for two container full to reach your goal.

If you give me your acutal tank (system volume minus rock,sand equipment) and top off container volume I can help you if you have trouble. ;)

[sefrayser]

Its a 34G solana. WIth the rock and sand the calculator said 29.8 so I rounded it to 30 gallons. My reading is 1.023 or 30. I would like it at 1.025 or 35. I have a 4 gallon ATO reservoir. Its actually 17 qt but 4 gallon is close enough.

[bertoni]

I'd just top off with saltwater at 35 ppt, which is more like 1.026 SG, if you're talking about the standard units at 25 C or so, I think.

[sefrayser]

Well I am going to try the calculator first and see how it goes. I mixed the water at 1.014. I will check in a couple days. It cannot hurt, its better than straight RO water.

[bertoni]

That should be about right. :)

[HighlandReefer]

Well I am going to try the calculator first and see how it goes. I mixed the water at 1.014. I will check in a couple days. It cannot hurt, its better than straight RO water.

Sounds good. ;)

If the calculation does not work out right, then you can simply adjust your total water volume to get the correct answer. So this calculator can help determine your actual total water volume more closely given your top-off reservoir & method of measuring salinity is likely correct. :)

[TheH]

sefrayser, 1.025 sg is roughly equal to 33.2 ppt, not 35 ppt. That is the source of this confusion.

You should keep your ATO at 1.015 sg (1.0149 sg). When all four gallons have been added to the tank, the tank's salinity will have moved from 30.5 ppt (1.023 sg) to 33.2 ppt (1.025 sg).

[TheH]

Cliff, that is an interesting idea I actually have a calculator dedicated for that:

http://www.hamzasreef.com/Contents/Calculators/SystemVolume.php

I was thinking of re-doing it with some ion that isn't rapidly consumed but can be measured with more accuracy than overall salinity.

[HighlandReefer]

Love your calculators. :thumbsup: